There is a generalized requirement for the military, other related defense agencies and other users of explosives to safely detonate explosives. Safely in this context means: safely separated in distance, safely separated in time and security of initiation. Explosives are initiated by electrical circuit cable or other non-electrical ‘cable’, but if the cable must be run for a great distance (from hundreds of meters up to several km) or there are multiple circuits again entailing substantial cable lengths, remote initiation by radio signal becomes highly desirable. Also in cases of electrical initiation, long cable lengths allow greater susceptibly to initiation of the charge via electro-magnetic induction onto the cable (radio signals or lightning strikes).
Security of initiation requires that the explosive must not be initiated falsely, either because of erroneously decoded signals or deliberately spoofed signals. Also to ensure the extremely high level security required, the equipment must be protected against the possibility of the failure of microprocessors and the program code. The firing circuits must also be designed and analyzed to a very high standard to ensure that component failure will not result in the firing voltage being incorrectly applied to the explosive circuit.
The remote initiation equipment needs to be as small in volume and as light weight as possible. The radio transmission system needs to operate over a good distance; line-of-sight to 25 km, ground to ground, in a rural environment of 10 km and 3 km in an urban environment. The equipment needs to be very robust, being carried in an environment that includes; temperatures from −40° C. to +60° C., water depths of 20 meters and in aircraft flying to 30,000 ft.
Another desirable feature would be to include a timed initiation function that would still allow remote initiation over-ride.
Operation from ordinarily available disposable batteries is very desirable. The receiving unit needs be able to be deployed for up to 15 days and still initiate the explosive at the end of a 300 meter cable.
The operation of the equipment must be safe, simple, and easy to train soldiers in its use. The operator must have time to withdraw from the scene of operations before the equipment becomes active. The signalling protocol of equipment must allow for a good deal of flexibility of deployed receiving equipment numbers, combinations of simultaneous and separate detonations to cover a large variation of operational requirements.
Current Remote Initiation Equipment
Current RI equipment is bulky and heavy with weights around 1.5 kg and volumes around 1500 cubic cm. This weight and volume is driven by the need to increase power endurance which leads to existing cumbersome battery solutions. Further the frequency bands may not be well chosen to achieve the required distances. This can also lead to increased power demand through the selected transmitter power level.
Some current equipments attempt to increase distance by providing retransmission units, i.e. a receiver captures the signal halfway down range and couples it to another transmitter that repeats it onward to the ultimate receiver (possibly multiple times). However, this greatly increases the system complexity, set up times and weight of the total system (at least 4 bulky items with associated batteries).
The reliability of a single microprocessor can be suspect, as either a simple failure of the electronic machine or an untested software path could result in the triggering of the firing circuit. The safest assumption to make about a microprocessor and its program is that it could arbitrarily decide to initiate a firing event. To guard against such an event, a secondary processor with its own independent control of the firing circuit can be incorporated.
No inexpensive, safe expendable remote initiation expendable receiver is known to be available within current product ranges.
Disadvantages of Existing Remote Initiators
Safety: It is not known of any prior equipment with the safety design of the invention hereinafter described.
Volume and Weight: The volume and weight of known prior equipment is at least three times greater than the invention.
Power Endurance: The power endurance of known prior equipment is less than or equal to the endurance of the invention. While the invention does not use special to type batteries rather simple primary cells available from most stores.
Ease of Use and Training: None of the existing remote initiators provide simplicity of use. A considerable amount of training and experience is required in any but the most simple of deployments.
Operational Radio Range: Radio ranges of current systems fall short of the ranges desired by the user community.